EMB~~rA• CPâlSACOMPARISON BETWEEN FURROW AND DRIP IRRIGATIONOF MELON IN THE sÃO FRANCISCO REGION

BY

A.F. OLITTAI, T.A. ABREU2, and D.B.MARCHETTI3

SYNOPSIS -- In the Semi-Arid Tropic Research Center (EMBRAPA), Petrolina, PE,Brazil, an irrigation experiment with melon (Valenciano Amarelo var.) wasconducted. Two methods were used: furrow irrigation, normally used in there~ion, and drip irrigation, a new tecnology that was tested, where the mainobjective was to determine some important factors in irrigatian managem~nt.

The data have shown that the drip method of irrigation furnished the bestresults, at 0.7 atm sail water leveI and with 1 emitter per four p1ants.

INTRODUCTION

The são Francisco Region in Northeast Brazil has a very great potentialin growing melons, due to local climate and soil characteristics that allowsexcel1ent fruit quality. lfuenoptima1 fertilizer applications are given, themain factor affecting melon yields are soil moisture because of the normalwater deficit.

When a solution 1ike irrigated agriculture is proposed to the NortheastRegion, it is essentia1 to choose the exact place and the proper crop. Melonsneed high air temperature as well as high soi1 temperature, being just thecucumis specie more hard to satisfy in heat. This explain the excellentqua1ity of melons produced in that Region.

This experiment was proposed to collect data related to the behavior ofmelon crop under drip and furrow irrigation methods as well as some factorsrelated to drip irrigation management.

I REVIEW OF LITERATURE

SHMUELI and GOLDBERG (1971) working in a comparison of sprinkle, furrowand trickle irrigation applied to muskmelon, found that vegetative growth wasmore rapid and yields were earlier and higher with the trickle method. Noyield differences were detected between sprinkle and furrow irrigation. The

lAssistant Professor, Escola Superior de Agricultura Luiz de Queiroz,Universityof são Paulo, Piracicaba, SP, Brazi1.

2Researcher, Centro de Pesquisa Agropecuãrio do Tropico Semi-Ãrido (EMBRAPA),Petro1ina, PE, Brazil.

3Empresa Brasileira de Pesquisa Agropecuãria (EMBRAPA), Brasília, DF, Brazil.

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increasing growth rate of muskmelon plants irrigated by trickling was mainlydue to the greater numher of leaves on the individual planto The increasedyield by trickling could be attributed in part to the greater number of fruitper plant which reached marketable size. and in part to the greater number oflarge fruit.

In a two year experiment with melons irrigated by the drip method. DAN(1974) found a trend to a h í gher total and early yield wi th Lower quantitiesof water applied. The same results were get in relation to more and earlierfruits per planto

During a three year experiment. 1971 to 1973. lvILLARDSON. BOHN and HUBER(1974). concluded that higher yields per'unit of water were obtained withdrip irrigation over furrow irrigation of cant~lupe cultivars. but at theexpense of reduced total yield.

GOLDBERG, GORNAT and RPfO~~ (1976) cornmen t s that the o u t s t and ing re s u I t sunder drí.pirrigation in cucurbi t s pLan t s can be at tributed to the followingfactors: the maintenance of Low soil water tension favours plant development;the application of fertilizers through the drip system at frequent intervalshelps increase yields and disease due to wetting the foliage ouring irrigationin reduced.

MATERIAL AND METHODS

The experiment was conducted in the Semi-Arid Tropic Research Center(EMBRAPA). Petrolina. PE. The soil is gross textured. alluvion type and thelocal climate was classified as very arid by HARGREAVES (1974). Melons of theValenciano Amarelo variety were planted on the 6/14/76. at 1.5 x 2.0 m spacingand the cultural practices were those whi ch are normal for this crop, Ageneral view of the experiment is shown in Figure 1.

Furrow is the method of irrigation normally used for conducting meloncrops in the Region. The experiment was designed for comparing this method tothe drip irrigation tecnique. For the furrow irrigation. short rows 18 m inLerigh t , 0.2% slope, were employed in order to achieve uniform ,.,aterapplication. The water system distribution was made also with polyethilenepipes as you can see in Figure 2. and the water applied per irrigation wasmetered for each treatment through automatic metric valves. This allow us tohave a exactly irrigation controlo

The control head of the drip system was located in front of the field andincluded diesel pump. fertilizer injector, sand filter, screen filter.pressure regulators. automatic metric valves and hydrometers (Figure 3). Thesethree last components were used individually for each one drip irrigatedtreatment. allowing a double mettering of the water applied per irrigation.The emitter was a multiple-exit long-path type (IRRIGA), having each one fourindividuaIs microtube. and giving at 10 m working pressure~ a total dischargeof 13 l/h. The sistem water distribution using poliethilene pipes weredesigned to possibilite individual water application in alI treatments,independent of each one.

Manure and chemical fertilizers were given prior to planting. as is

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customary in the Region. Nitrogen was added in four applications during thegrowing period to complete the amount indicated hy sai1 analysis. It wasapplied in liquid form through the drip system and as solid in the furrowirrigation method.

The experimental design envolving the two methods of irrigation andsoil water leveI was rep1icated four times in a randomized block design.within the drip irrigation treatments was tested three different numbersemitter per p1ant. The fo11owing treatments were setted up:Treatment 1 drip irrigation, soi1 water at 0.4 atm, 1 emitter/4 plantsTreatment 2 drip, 0.4 atm, 1 emitter/2 plantsTreatment 3 drip, 0.4 atm, 1 emitter/p~antTreatment 4 drip, 0.7 atm, 1 emitter/4 plant~Treatment 5 drip, 0.7 atm, 1 emitter/2 plantsTreatment 6 drip, 0.7 atm, 1 emitter/plantTreatment 7 - furrow. 0.4 atmTreatrnen t 8 - f urrow , 0.7 atm

twoAlso,

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Growth rates were determined by sampling eight plants per treatment in thefourth b10ck each 20 days, during alI the growing period. Five parcelledharvests were made during the period of September, 2 to October, 10, 1976.Mercury tensiometers in number of 16, were used for irrigation contro1 at 15

'and 30 cm depth. The irrigation time was ca1culated according to KELLER and'KARMELI (1975), based on a wetting factor of 40%. There was no precipitationduring alI the growing period of the crop. Evapotranspiration rates averagefor 15 days period were ca1culated by the HARGREAVES (1974).

DISCUSSION OF RESULTS

Growth rates, determined by weighing entire plants and counting the numberof leaves per plant, are presented in Figure 4. The rates were different forthe two methods, with the highest from any of these three consideredparameters, in the drip irrigation method. The rates were particularly high inthe period between 30 to about 60 days from planting.

The analysis of Figure 5 shows a greater accumulated yield per harvestingduring alI the period for the drip irrigation treatments at the 0.7 atm soi1water leveI. The increased yield by dripping can be attributed in part to thegreater number of fruit as well as the greater average size of the fruitsobtained in the parcelled harvests (Figure 6). The smal1est values of thesetwo parameter were obtained in the furrow irrigation at the saroesoil waterleveI. I.:::

1-:e:iOIn Tab1e 1 is presented the total production of melons expressed in Kg/ha~';:'::_

It was considered only three replications because the fourth one was used for cvegetative growth sampling. As a cultural practice normally used in the .)Region, each plant was conditioned to produce on1y two fruits, being the .~flowers and small fruits eliminated continuously with plants growth. So, for "a 20 useful plants per plot the total of 80 fruit was extrapolated to kg/ha. ~

The statistical analysis of these data as randomized blocks with eighttreatments and three replications, showed that the mainly significant

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Considering only the general average yield of the drip and furrowtreatrnents,respectivelly 11,846 and 7,94i Kg/ha, the increased yield is 497..This consideration is rnadeprorninent for the dFip irrigation rnethod at the 0.7atrnsoil water leveI (Figures 5 and 6). Furthernore we can say that 1 ernitterper four plants is the rnosteconornical arrangernent for drip systerndesign,because this arrangernent utilize only one lateral line per two raws aE plants.

difference·occurred between the irrigation methods comparison when consideringtotal yield. No significance was found in the individual analysis of each oneoE the pareelled harvest. AIso no statistieal differenee was faund within soilwater leveI control for each one of the two methods of irrigation, and for thenumber of ernitterper plant in the drip method.

The expanded statistieal analysis has detected the effeet of soil waterleveI and the number of emitter per plant only in the third harvest production.This can be visualized in Figure 5 by the produetion increase the 0.7 atrntreatrnents.

Fruit quality before and after a storage period was analysed and theresults are showed in tabIe 2.

CONCLUSIONS

MeIon erop in the são Francisco Region, Brazil, responded differently tothe method utilized for applying water. Greater grm.;rthrate and higher yieldswere obtained with drip irrigation over furrow irrigation. Taking intoconsideration irrigation management and equipment arrangement, soil water leveIat 0.7 atrnand 1 emitter per four plants gave the best results.

LITERATURE CITEDDAN, C. (1974), "Influence of different Amounts of Irrigation-Hater,Irrigation-

-Intervals and Fertilizers on the Yield and Quality of Drip Irrigated Muskand l-latermelons",Proceedings of the Second International Drip IrrigationCongress, San Diego, California, pp. 425-430.

GOLDBERG, D., GORNAT, B., and RU10N, D. (1976), Drip Irrigation-principles,design and cultural practices, Drip Irrigation Scientific Publications,Israel.

HARGREAVES, G.H. (1974), Potential Evapotranspiration and IrrigationRequirements for Northeast Brazil, Utah State University, Logan, Utah.

KELLER, J., and KARMELI, D. (1975), Trickle Irrigation Design, Rain BirdManufacturing Corporation, Glendora, California.

SHMUELI, M., and GOLDBERG, D. (1971), "Sprí.nkLe, Furrow and Trickle Irrigation '~of Muskemelon in a Ar í d Zone", HortScience, Volume 6, Number 6, pp.557-559.~-,...

WILLARDSON, L.S., BOHN, G.W., and HUBER, M.J. (1974), "Cantalupe Responses toDrip Irrigation", proceedings of the Second International Drip IrrigationCongress, San Diego, California, pp. 474-477.

Tab1e 1. Total yie1d of me10ns (Kg/ha)

Treatment Rep1. 1 Repl. 2 Rep1. 31 12,327 13,195 10,1472 10,254 10,345 10,1643 11,736 7,621 12,5974 11,172 14,443 12,8235 12,717 14,640 14,0906 9,908 15,027 10,0177 5,170 14,581 7,4348 6,219 9,48~ 4,725

Tab1e 2. Chemica1 ana1ysis of the me10n fruit

Brix Acidity B/ATreatment • !

O day 20 days O day 20 days O days 20 days

1 12.8 12.6 0.16 0.20 80.0 63.02 12.8 12.5 0.15 0.18 85.5 69.43 12.1 11.8 0.14-- 0.18 86.4 - 66.04 12.5 12.3 0.18 0.17 69.4 72.45 12.3 12.4 0.14 0.17 87.8 72.96 12.2 11.6 0.15 0.16 81.3 72.57 12.2 11.5 0.12 0.16 95.8 76.28 12.2 11.5 0.14 - _0.18 87.1 63.8

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Figure 4. Melon growth rate under drip and furrow irrigation.

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Figure 5. Average yield per harvest.

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Figure 6. Average size per harvest of melon fruits.

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